Would the leaders of the world be less argumentative if we brought back 'court jesters'?

Way back when in the Middle Ages, British royalty had court jesters to entertain the royal household and its guests. Britain even licensed them as “royal fools”.

More importantly, they could say insulting (and true!) things to the King’s face and not get in trouble.

Would court jesters be useful today, for Putin, Kim Jung Un, Assad in Syria, and perhaps the current leader in Saudi Arabia?